rf203_ranges.C File Reference

Detailed Description

Fitting and plotting in sub ranges.

 
#include "RooRealVar.h"
#include "RooDataSet.h"
#include "RooGaussian.h"
#include "RooConstVar.h"
#include "RooPolynomial.h"
#include "RooAddPdf.h"
#include "RooFitResult.h"
#include "RooPlot.h"
#include "TCanvas.h"
#include "TAxis.h"
#include "TH1.h"
using namespace RooFit;
 
void rf203_ranges()
{
   // S e t u p   m o d e l
   // ---------------------
 
   // Construct observables x
   RooRealVar x("x", "x", -10, 10);
 
   // Construct gaussx(x,mx,1)
   RooRealVar mx("mx", "mx", 0, -10, 10);
   RooGaussian gx("gx", "gx", x, mx, RooConst(1));
 
   // Construct px = 1 (flat in x)
   RooPolynomial px("px", "px", x);
 
   // Construct model = f*gx + (1-f)px
   RooRealVar f("f", "f", 0., 1.);
   RooAddPdf model("model", "model", RooArgList(gx, px), f);
 
   // Generated 10000 events in (x,y) from pdf model
   RooDataSet *modelData = model.generate(x, 10000);
 
   // F i t   f u l l   r a n g e
   // ---------------------------
 
   // Fit pdf to all data
   std::unique_ptr<RooFitResult> r_full{model.fitTo(*modelData, Save(true), PrintLevel(-1))};
 
   // F i t   p a r t i a l   r a n g e
   // ----------------------------------
 
   // Define "signal" range in x as [-3,3]
   x.setRange("signal", -3, 3);
 
   // Fit pdf only to data in "signal" range
   std::unique_ptr<RooFitResult> r_sig{model.fitTo(*modelData, Save(true), Range("signal"), PrintLevel(-1))};
 
   // P l o t   /   p r i n t   r e s u l t s
   // ---------------------------------------
 
   // Make plot frame in x and add data and fitted model
   RooPlot *frame = x.frame(Title("Fitting a sub range"));
   modelData->plotOn(frame);
   model.plotOn(frame, Range(""), LineStyle(kDashed), LineColor(kRed)); // Add shape in full ranged dashed
   model.plotOn(frame);                                                     // By default only fitted range is shown
 
   // Print fit results
   cout << "result of fit on all data " << endl;
   r_full->Print();
   cout << "result of fit in in signal region (note increased error on signal fraction)" << endl;
   r_sig->Print();
 
   // Draw frame on canvas
   new TCanvas("rf203_ranges", "rf203_ranges", 600, 600);
   gPad->SetLeftMargin(0.15);
   frame->GetYaxis()->SetTitleOffset(1.4);
   frame->Draw();
 
   return;
}

 
[#1] INFO:Minimization -- RooAbsMinimizerFcn::setOptimizeConst: activating const optimization
[#1] INFO:Minimization --  The following expressions have been identified as constant and will be precalculated and cached: (px)
[#1] INFO:Minimization --  The following expressions will be evaluated in cache-and-track mode: (gx)
[#1] INFO:Minimization -- RooAbsMinimizerFcn::setOptimizeConst: deactivating const optimization
[#1] INFO:Eval -- RooRealVar::setRange(x) new range named 'signal' created with bounds [-3,3]
[#1] INFO:Eval -- RooRealVar::setRange(x) new range named 'fit_nll_model_modelData' created with bounds [-3,3]
[#1] INFO:Fitting -- RooAbsOptTestStatistic::ctor(nll_model_modelData) constructing test statistic for sub-range named signal
[#1] INFO:Minimization -- RooAbsMinimizerFcn::setOptimizeConst: activating const optimization
[#1] INFO:Minimization --  The following expressions have been identified as constant and will be precalculated and cached: (px)
[#1] INFO:Minimization --  The following expressions will be evaluated in cache-and-track mode: (gx)
[#1] INFO:Minimization -- RooAbsMinimizerFcn::setOptimizeConst: deactivating const optimization
[#1] INFO:Plotting -- RooAbsPdf::plotOn(model) p.d.f was fitted in a subrange and no explicit NormRange() was specified. Plotting / normalising in fit range. To override, do one of the following
   - Clear the automatic fit range attribute: <pdf>.removeStringAttribute("fitrange");
   - Explicitly specify the plotting range: Range("<rangeName>").
   - Explicitly specify where to compute the normalisation: NormRange("<rangeName>").
   The default (full) range can be denoted with Range("") / NormRange("").
[#1] INFO:Plotting -- RooAbsPdf::plotOn(model) only plotting range ''
[#1] INFO:Plotting -- RooAbsPdf::plotOn(model) p.d.f. curve is normalized using explicit choice of ranges 'fit_nll_model_modelData'
[#1] INFO:Plotting -- RooAbsPdf::plotOn(model) p.d.f was fitted in a subrange and no explicit Range() and NormRange() was specified. Plotting / normalising in fit range. To override, do one of the following
   - Clear the automatic fit range attribute: <pdf>.removeStringAttribute("fitrange");
   - Explicitly specify the plotting range: Range("<rangeName>").
   - Explicitly specify where to compute the normalisation: NormRange("<rangeName>").
   The default (full) range can be denoted with Range("") / NormRange("").
[#1] INFO:Plotting -- RooAbsPdf::plotOn(model) only plotting range 'fit_nll_model_modelData'
[#1] INFO:Plotting -- RooAbsPdf::plotOn(model) p.d.f. curve is normalized using explicit choice of ranges 'fit_nll_model_modelData'
result of fit on all data 
 
  RooFitResult: minimized FCN value: 25939.4, estimated distance to minimum: 7.58116e-06
                covariance matrix quality: Full, accurate covariance matrix
                Status : MINIMIZE=0 HESSE=0 
 
    Floating Parameter    FinalValue +/-  Error   
  --------------------  --------------------------
                     f    5.0441e-01 +/-  6.32e-03
                    mx   -2.1605e-02 +/-  1.77e-02
 
result of fit in in signal region (note increased error on signal fraction)
 
  RooFitResult: minimized FCN value: 10339.5, estimated distance to minimum: 3.38989e-07
                covariance matrix quality: Full, accurate covariance matrix
                Status : MINIMIZE=0 HESSE=0 
 
    Floating Parameter    FinalValue +/-  Error   
  --------------------  --------------------------
                     f    4.9014e-01 +/-  1.62e-02
                    mx   -2.1701e-02 +/-  1.79e-02
 

Date

July 2008

Author

Wouter Verkerke

Definition in file rf203_ranges.C.